1. Field of the Invention
The present invention relates to a cooling apparatus for a construction machine.
2. Description of the Related Art
Heretofore, as a cooling apparatus for a construction machine, there has been known one type designed to allow cooling air sucked by a cooling fan to pass through respective cores of a plural number of heat exchangers arranged in widthwise side-by-side relation to each other to thereby perform heat exchange (see, for example, JP 2010-159691A: hereinafter referred to as “Patent Document”).
In a cooling apparatus disclosed in the Patent Document, two cores having different heights are arranged in side-by-side relation, due to the restriction of installation space. Therefore, in order to suppress vibration and noise, an inter-core step region where a projection of the cooling fan does not fall within (i.e., protrudes from) a surface of the two cores is expanded in a radially outward direction of the cooling fan to form a volume increase portion, or a bypass air passage is provided to lead air behind the cores to the inter-core step region.
However, the cooling apparatus disclosed in the Patent Document is primarily intended to suppress vibration and noise due to a difference in height between the cores. Thus, it is not designed considering that a variation in air volume occurs due to a difference in airflow resistance between the cores.
Specifically, the cooling apparatus disclosed in the Patent Document comprises two generally rectangular-shaped cores having different heights, wherein a region failing to overlap the projection of the cooling fan exists above an upper edge of a lower one (hereinafter referred to as “lower core”) of the two cores (a relatively large region which extends beyond the upper edge of the lower core and the projection). The cooling fan has a circular shape, and an air-volume distribution of cooling air passing through the cores concentrates in a region corresponding to the projection of the cooling fan. Thus, there remains the need for improvement in terms of cooling efficiency.